DIGITAL THERMAL GAS RHEOMETER INSERTABLE INTO PIPING TUBES

摘要

Novelty: a digital thermal gas rheometer vertically insertable into each tube of a piping system of varying dimensions. Constitution: the shell (3) is suitable for use with oxidising gases and sealedwith flanges set into grooves (4,5). Feeding and exit signals are transmitted from and to the internal circuits via the cable (2). The invented rheometer has a digital, analogous or mixed signal exit; it measures the flow via a microscopic micro-electro-mechanical sensing element (12) (MEMS) in 7,1mm x 3.1 mm dimensions which is made of silicon with MOS processes (Metal Oxide Semiconductor). The element operates on the base of the thermal principle and has heating resistances (20,21) and reference resistances (22, 23) positioned onto different 2μm-thick silicon membranes (26,27) allowing the goodthermal isolation and response of the aforementioned resistances which are connected in stable temperature conditions and able - due to their symmetrical arrangement - to be used for the two-way flow measurement. Advantages: the invented rheometer is an evolution of the existing devices since it offers enhanced two-way flow accuracy and detection inside a very small mechanical shell.